ASE A5 Brakes Practice Test
36. After a test drive, one brake rotor is much hotter than the others. Which of the following is causing this condition?
- A. A frozen brake caliper.
- B. Frozen slide pins.
- C. A sticking caliper piston seal.
- D. Aerated brake fluid.
Answer A is wrong. A frozen brake caliper causes the vehicle to pull to the side with the functioning caliper.
Answer B is wrong. Frozen slide pins cause uneven pad wear with floating caliper brake systems. If the slide pins are frozen, the outboard pad doesn't slide into contact with its side of the rotor. The inside pad is doing most, if not all, of the braking.
Answer C is correct. If the seal does not retract the piston, the brake drags as the pad stays in contact with the rotor. Overhaul kits contain a new boot and seal. Square cut piston seals, and other rubber components are sensitive to water, oil, and brake fluid contamination.
Answer D is wrong. Friction causes the rotor to overheat, deform, and warp. It can cause the vehicle to pull to the side that's dragging.
37. Technician A says the residual check valves keep constant pressure on the wheel cylinder cup seals. Technician B says the residual check valve maintains pressure when the brake pedal is released. Who is correct?
- A. Technician A
- B. Technician B
- C. Both A and B
- D. Neither A or B
Answer A is wrong. Residual check valves are used on drum brake systems to keep around 5 psi. - 12 psi. of pressure on the wheel cylinder's cup seals.
Answer B is wrong. The valve is keeping constant pressure on the system; any small leaks result in fluid leaking out instead of air leaking into the system. Residual check valves keep constant pressure on the wheel cylinder's cup seals.
Answer C is correct. Residual check valves keep constant pressure on the wheel cylinder's cup seals.
Answer D is wrong. They consist of a check valve and spring located inside the master cylinder port leading to the rear drum brakes.
38. One of the brake shoes on the rear drum brakes has worn more than the other. Which of the following is causing this condition?
- A. Overadjusted brake shoes.
- B. A sticking wheel cylinder.
- C. Weak brake springs.
- D. A leaking wheel cylinder.
Answer A is wrong. Overadjusting the brake shoes results in premature wear, and can also cause brake lockup with only light pedal pressure.
Answer B is correct. Wheel cylinders contain pistons that can stick, affecting brake shoe application. It may be hard to notice without inspection because the other shoe is contacting the drum and slowing the vehicle.
Answer C is wrong. Heat and fatigue can wear brake springs; it results in brake binding and drag.
Answer D is wrong. Leaking internal cup seals are the most common problem encountered with wheel cylinders.
39. A vehicle with a four-wheel disc ABS brake system has a slight clicking sound when it's first started in the morning. The noise goes away after a few seconds. Which of the following is MOST likely making this noise?
- A. The brake switch.
- B. The ABS modulator assembly.
- C. The brake pads are shifting.
- D. The vacuum brake booster.
Answer A is wrong. A faulty brake switch typically results in brake light failure. The ABS pump/modular assembly contains a pump and valves that sometimes click when activated. When a vehicle is first started or has been sitting for a while, an audible click is normal.
Answer B is correct. The ABS system runs a system check when the key is first turned to the ON position. The valves sometimes make a clicking noise during this check.
Answer C is wrong. Loose brake pads can make a clunking sound when the brake is applied.
Answer D is wrong. Brake boosters hiss but do not make a clicking noise. The ABS brake system runs a system check when the vehicle is first started. During normal operation, the system lies dormant, and the standard brake system is used.
40. The rear drum brakes of a light truck are locking up with only light pressure applied to the brake pedal. Which of the following is causing this condition?
- A. A faulty proportioning valve.
- B. The pressure differential switch.
- C. A faulty metering valve.
- D. A faulty brake switch.
Answer A is correct. A faulty proportioning valve results in the rear brakes locking up with only light to moderate pressure applied to the brake pedal. They lock up as the vehicle's weight is shifted toward the front wheels.
Answer B is wrong. The pressure differential switch warns the driver of a hydraulic leak.
Answer C is wrong. A brake metering valve, similar to the proportioning valve, is also used to achieve balanced braking. Front-disc rear-drum brake systems use the valves. The metering valve delays fluid pressure to the front calipers just long enough to overcome the rear brake springs and linkage. This delay achieves even brake application of the front and rear brakes.
Answer D is wrong. The brake switch is part of the brake light system.